1. The Effects of HCl and NaOH on Catechol
Mrs. Potter’s 5th and 6th Period Class
Franklin High School, Stockton, California
ABSTRACT
In our experiment we researched the effects that HCl and NaOH would have on catechol, a chemical found in potatoes. Its is a substance is in fruits and vegetables which turns brown when exposed to oxygen. HCl and NaOH was mixed thoroughly with potato extract and catechol. The reaction was tested with a spectrophotometer. Our results show that NaOH increased the activity of catechol than HCI, and that the concentration of the base or the acid did not effect catechol activity.
RESULTS
The results showed that NaOH had a higher activity than HCl. The concentration of the base did not affect catechol oxidase activity. The highest activity in the acid was observed at 1.0 M HCl. The lowest activity was observed at 0.4 M HCl. The highest activity in the base was observed at 0.4 M NaOH. The lowest activity in the base was observed at 0.3 M NaOH.
METHODS
Hydrochloric acid and sodium hydroxide acid was diluted to the desired concentration. 100 grams of pealed potato was blended in 300 ml of distilled water and strained through a coffee filter. The catechol used was 1% w/v. The chemicals were thoroughly mixed according to Table 1. The absorbance was measured at 440nm with the spectrophotometer-meter after waiting a period of 5 minutes.
DISCUSSION
Our results showed that the concentration of HCl and NaOH did not effect the activity of catechol oxidase. However, HCl was shown to inhibit activity while NaOH increased activity. Perhaps catechol activity would be affected by different pH levels. 1.0 M HCl had the highest activity among the acids. It may be possible that increases in acid concentrations will restore the activity of catechol oxidase. Exposure to oxygen increased catechol activity as expected and observed in the potato extracts. Our findings can be used to keep foods with catechol from turning brown. By simply adding a small amount of acid to any fruit containing catechol such as avocados, apples, and bananas, etc. catechol activity can be inhibited. Catechol can also be prevented under anaerobic conditions. The combination of acids and anaerobic conditions would work together to preserve foods containing catechol.
INTRODUCTION
An anti-fungus known as Catechol is a substance found in vegetables and fruits that when exposed to oxygen, by simply pealing the skin, it turns that particular area of the fruit brown. It’s possible to prevent or at least decrease the amount of catechol activity by putting an acid on the fruit or vegetable. People typically use lemon as the acid. Our research project was how HCl and NaOH concentrations effect the activity of catechol in a potato extract. To approach this, we measured catechol activity at different concentrations with a spectrophotometer. We hypothesized that if HCl will inhibit catechol activity and NaOH will increase catechol activity, then acids will show lower reading on the spectrophotometer than those of the bases.
Catechol
Extract
Water(acid/base) #1 X
1mL
4mL #2 #3
3mL